1. Field of the Invention
The present invention relates to a motor vehicle door lock such as a side door lock, a rear door lock, a rear hatch lock, a hood lock or the like, and the use of a diode in the motor vehicle door lock.
2. Description of the Related Art
Published German Patent Application DE 197 97 211 A1 discloses a motor vehicle door lock which has an electric motor for driving the actuating element. However, since the electric motor can only be operated in one direction of drive rotation, the poling of the drive DC voltage is not changed. Moreover, the motor vehicle door lock has completely self-locking gearing in the form of a worm gear which can be driven by the electric motor and which acts on the actuating element which is made as a worm wheel. The actuating element is provided with a driving journal which can act on the detent pawl of the motor vehicle door lock for pivoting the detent pawl. The detent pawl has an abutment stop against which the driving journal of the actuating element runs in the pivoting position of the detent pawl so that further rotary motion of the actuating element, and thus, rotary motion of the electric motor is blocked in the direction of drive rotation temporarily as long as the detent pawl is in this pivoting position.
In the aforementioned blocking there is the danger that the actuating element again moves back against the direction of motion which is effected when the electric motor turns in the direction of drive rotation, as is explained in German Patent Application DE 197 47 211 A1. The aforementioned shifting motion of the actuating element when blocked by an abutment stop is undesirable and is to be avoided. In this respect German Patent Application DE 197 47 211 A1 calls for mechanical blocking of the actuating element for prevention of reversed motion, however, mechanical blocking is complex and sensitive.
An object of the invention is to provide a motor vehicle door lock including the use of a diode in the motor vehicle door lock so that the backward motion reversal of the actuating element which is driven by the electric motor can be minimized easily, economically and less susceptibly.
The object is achieved by connecting a diode parallel to the electric motor which, when the electric motor is turned off, minimizes the reversal of the electric motor by means of the voltages which occur when the electric motor is reversed being more or less short circuited, or at least greatly reduced via the diode, by which very strong braking of the electric motor results. Consequently, in this way the undesirable backward motion of the actuating element which is connected directly to the electric motor or especially indirectly via gearing is minimized.
An advantageous result in the present invention is that a mechanism for blocking the backward or reversing motion is not necessary. A diode is available very economically. Accordingly a simple, economical approach arises. Another advantageous result is that a diode is not subject to wear. Consequently, the susceptibility or failure probability is greatly improved relative to the prior art. This is a major advantage especially with respect to the required long life in motor vehicle components. Another advantage of avoiding mechanical blocking of the actuating element against unwanted backward or reversing motion is the reduction of noise, since mechanical systems in operation always produce noise. Moreover, the diode can be used for interference suppression since voltage peaks can be diminished via the diode when the electric motor is turned off. Accordingly, an electronic component for motor interference suppression which is generally otherwise necessary can be eliminated by the use of a diode as claimed in the invention.
Other details, features, objectives and advantages of this invention are detailed below using the drawings of one preferred embodiment.